Hypernatremia and hyponatremia Flashcards Preview

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Flashcards in Hypernatremia and hyponatremia Deck (16)
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1

What is the classification of hypernatremia

>145 mM

2

Underlying physiology causes of hypernatremia

High sodium intake

Loss of fluid volume (more water)
- sweating/dehydration/diarrhea

Low levels of ADH

Hyperaldosteronism

Diabetes insipidus (Central and nephrogenic)

Hypothalamic lesions

Osmotic diuresis
- use of mannitol, high protein time feedings, glucose in uncontrolled diabetes

Severe exercise or seizures

***measured plasma Na+ concentration does not always imply hyper or hyponatremia! NEED to determine sodium concentration with respect to total volume present***

3

Common Symptoms of hypernatremia

AMS

Lethargy

Seizures

Extreme thirst

Muscle twitching/spasms

4

What are the percentages to use when estimating total body water?

50% females

60% males

5

Treatments for hypernatremia

#1 is IV fluids or oral replacement with water

Desmopressin next line usually

6

What are common IV solutions?

Hypertonic = 3% normal saline

Isotonic = 0.9% normal saline or ringers

Hypotonic **use this for hypernatremia**
- 0.45% normal saline
- D5W (5% dextrose in water)

7

What is the diagnostic value of hyponatremia?

Na <135mM

8

Etiologies of hyponatremia

*Very large amount of etiologies*

**Very common in hospitalized patients (22%)

Low sodium or excessive water intake

Increased effects of vasopressin in clincial use

9

Clinical symptoms of hyponatremia

Nausea/headache

vomiting

AMS

Abdominal Cramping or distal leg cramping

** if sodium dips below <120mM**
- seizures
- coma
- brainstem herniation
- death

10

Acute vs chronic hyponatremia

Acute:
- <48hrs
- much more serious
- often iatrogenic (hospital cause or inappropriate use of hypotonic fluids/vasopressin)

Chronic:
- >48hrs
- less serious but still important
- usually a cause of physiological correction attempts but doesn’t work properly

11

Common causes of acute hyponatremia

Post up iatrogenic fluids/VP

Post-op/ pre-op iatrogenic glycine irrigation

Colonoscopy prep improperly

Premenopausal women

Recent/improper use of thiazides

Polydipsia

MDMA use

Extreme exercise without water replacement

12

Osmotic demyelination syndrome (ODS)

“Central pontine myelinolysis*

Usually due to a patient who is originally hyponatremic and is corrected way to fast
- damages the pons most

Results in fluctuating ECF/ICF volumes and neuronal damage

Symptoms: “acute onset of all”
- confusion
- delirium
- hallucinations
- dysphagia
- inability to balance properly
- slurred speech
- tremors

13

Causes of hyponatremia where the patient is euvolemic

Glucocorticoid deficency

Untreated Hypothyroidism

Stress

Drugs

SIADH

14

Tests to do when you have a hyponatremic patient

Plasma osmolatility

Urine sodium and urine overall osmolality

plasma glucose level
- if Patient has high glucose (add 1.6-2.4 mM to total sodium concentration for every 100mg/dl above normal)

15

Pseudohyponatremia

Increases or normal calculated serum osmolality in the presence of hyponatremia

*this is usually the cause of extreme proteins and lipid levels in the plasma compared to sodium*

***true hyponatremia shows low plasma osmolality and low sodium levels***

16

Methods of correct of hyponatremia

Restriction of water
- primary therapy in patients with edema, SIADH, primary polydipsia and advanced renal failure

Sodium chloride isotonic saline administration (also increased dietary salt)
- primary therapy in patients with true volume depletion or in adrenal insufficiency
- CANT use in edematous patients

Hypertonic saline = only acute symptomatic hyponatremia